Recuperação de n-butanol utilizando colunas de stripping à vácuo no processo de fermentação ABE
Arquivos
Data
2021-08-02
Autores
Gonçalves, Ellen Sandy [UNIFESP]
Ferreira, Michael Laia [UNIFESP]
Orientadores
Tovar, Laura Plazas [UNIFESP]
Tipo
Trabalho de conclusão de curso de graduação
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Resumo
O conceito de biorrefinaria vem ganhando grande destaque visto seu objetivo de transformar a biomassa em produtos de maior valor agregado, como os biocombustíveis, devido à crescente procura de fontes de energia renováveis. Dentre estes biocombustíveis, o n-butanol é obtido por meio do processo fermentativo ABE (acetona, n-butanol, etanol). O n-butanol possui um desempenho mais similar à gasolina quando comparado ao etanol, tornando vantajoso o uso deste combustível. Porém, ao atingir determinada concentração, o n-butanol torna-se inibidor da reação de fermentação. Neste trabalho foi analisado o processo de recuperação de n-butanol utilizando colunas de stripping à vácuo, por meio de simulações no ambiente computacional Aspen Plus™. Inicialmente, foi realizada uma análise para definir os modelos termodinâmicos mais adequados para o sistema estudado. Utilizando os modelos NRTL-HOC e UNIQUAC-HOC, o sistema reacional foi conformado a partir de uma corrente contendo glicose a 50 g L-1. Com isto, obteve-se uma corrente de saída do reator composta por n-butanol, água, etanol, ácido acético, acetona, hidrogênio e dióxido de carbono, além da glicose remanescente. Posteriormente, esta corrente foi ajustada por um separador/extrator, para que apenas n-butanol, acetona, etanol e água seguissem para o sistema de recuperação. Para este sistema foram estudadas duas conformações, a primeira composta por duas colunas de destilação e a segunda por duas colunas de stripping e uma de destilação. Ao final de ambas as conformações é obtida uma corrente composta por n-butanol e água, que serão separados em um sistema com duas colunas stripping. Foi obtida uma recuperação de n-butanol 87,43 % para a conformação 1 e 79,97 % para a conformação 2, além de uma pureza de 99,41 % para ambos os casos. Após estas simulações, foi realizada análise de sensibilidade variando-se os parâmetros de projeto e de operação das colunas, avaliando o impacto sobre a recuperação de n-butanol, pureza e consumo energético. A partir desta análise, foi possível determinar as melhores condições para estas colunas e, com base nestes valores, foram realizadas novas simulações. Atingiu-se uma recuperação de n-butanol de 100 % para a conformação 1 e de 99,82 % para a conformação 2, ambas mantendo a pureza de 99,41 %. Ao final do trabalho, concluiu-se que a conformação 1 é a mais vantajosa para a obtenção de n-butanol por possuir maior eficiência e menor consumo energético.
The biorefinery concept has gained great prominence given its objective of transforming biomass into greater added value products, such as biofuels, due to the growing demand for renewable energy sources. Among these biofuels, the n-butanol is obtained through the ABE (acetone, n-butanol, and ethanol) fermentative process The n-butanol has a more similar performance to gasoline than ethanol, making more advantageous the use of this fuel. However, when reaching a certain concentration, the n-butanol becomes a reaction inhibitor. This work aims to study the process of n-butanol recovery applying vacuum stripping columns by simulations in the software Aspen Plus™. Initially, an analysis was performed to define the thermodynamic models most suitable for the studied system. Using the models NRTL-HOC and UNIQUAC-HOC, the reactional system was conformed from a 50 g L-1 glucose stream. Thereby, a reactor output stream was obtained composed of n-butanol, water, ethanol, acetic acid, acetone, hydrogen, carbon dioxide, and the remaining glucose. Posteriorly, the stream was adjusted by a separator/extractor, obtaining a mixture of n-butanol, acetone, ethanol, and water which would continue to the recovery system. For this system two conformations were studied, the first one is composed by two distillation columns and the second one of two stripping columns and a distillation column. At the end of both conformations a stream composed of n-butanol and water is obtained in a system with two stripping columns. A recovery of 87.43% n-butanol for conformation 1 and 79.97% for conformation 2 was obtained, in addition to a purity of 99.41% for both cases. After these simulations, a sensitivity analysis was performed, varying the design and operating parameters of the columns, evaluating the impact on n-butanol recovery, purity and energy consumption. From this analysis, it was possible to determine the best conditions for these columns and, based on these values, new simulations were performed. N-butanol recoveries of 100% and 99.82 % were achieved for conformation 1 and conformation 2, respectively, both maintaining the purity of 99.41%. At the end of the work, it was concluded that conformation 1 is the most advantageous for obtaining n-butanol as it has greater efficiency and lower energy consumption.
The biorefinery concept has gained great prominence given its objective of transforming biomass into greater added value products, such as biofuels, due to the growing demand for renewable energy sources. Among these biofuels, the n-butanol is obtained through the ABE (acetone, n-butanol, and ethanol) fermentative process The n-butanol has a more similar performance to gasoline than ethanol, making more advantageous the use of this fuel. However, when reaching a certain concentration, the n-butanol becomes a reaction inhibitor. This work aims to study the process of n-butanol recovery applying vacuum stripping columns by simulations in the software Aspen Plus™. Initially, an analysis was performed to define the thermodynamic models most suitable for the studied system. Using the models NRTL-HOC and UNIQUAC-HOC, the reactional system was conformed from a 50 g L-1 glucose stream. Thereby, a reactor output stream was obtained composed of n-butanol, water, ethanol, acetic acid, acetone, hydrogen, carbon dioxide, and the remaining glucose. Posteriorly, the stream was adjusted by a separator/extractor, obtaining a mixture of n-butanol, acetone, ethanol, and water which would continue to the recovery system. For this system two conformations were studied, the first one is composed by two distillation columns and the second one of two stripping columns and a distillation column. At the end of both conformations a stream composed of n-butanol and water is obtained in a system with two stripping columns. A recovery of 87.43% n-butanol for conformation 1 and 79.97% for conformation 2 was obtained, in addition to a purity of 99.41% for both cases. After these simulations, a sensitivity analysis was performed, varying the design and operating parameters of the columns, evaluating the impact on n-butanol recovery, purity and energy consumption. From this analysis, it was possible to determine the best conditions for these columns and, based on these values, new simulations were performed. N-butanol recoveries of 100% and 99.82 % were achieved for conformation 1 and conformation 2, respectively, both maintaining the purity of 99.41%. At the end of the work, it was concluded that conformation 1 is the most advantageous for obtaining n-butanol as it has greater efficiency and lower energy consumption.